1. Field of the Invention
This invention relates to a seismic isolator for protecting a structure such as a building from vibrations such as an earthquake.
2. Description of the Prior Art
Conventional seismic isolators include generally those which interpose flexible members between a foundation and a structure and those which dispose vibration damping means and structure restoring means besides the flexible members.
In the conventional seismic isolators, however, a pull-out resistance force which inhibits upward displacement of a structure is small, and setting of a load bearing force, rigidity and horizontal deformation capacity per unit seismic isolator is limited. Furthermore, since these performance factors interfere with one another, the individual performance factors cannot be changed greatly.